Nano-composite phase-change antimony thin film for fast and persistent memory operations

Abstract

Elemental Sb phase-change material (PCM) has to be diminished to nanometer in thickness to guarantee non-volatile memory storage. Integrating ultrathin Sb films poses great challenges in manufacturing high-density phase-change random-access memory (PCRAM) chips. Here, we introduce another feasible approach of utilizing nano-composite Sb–SiO2 PCM, for which we demonstrate superior phase-change properties of faster crystallization speed and better data retention ability over the conventional Ge2Sb2Te5 compound. These two seemingly conflicting features of the Sb–SiO2 are reconciled by an obvious fragile-to-strong crossover in crystallization kinetics of the supercooled Sb liquids via nanosize confinements, enabling the more suffocated atomic diffusion near room temperature and the comparable crystal growth at elevated temperatures to the Ge2Sb2Te5. The nanosize confinements also catalyze heterogeneous nucleation remarkably, therefore speeding up the SET operation of the Sb–SiO2-based PCRAM device by over two orders of magnitude as compared to the Ge2Sb2Te5-based one. In addition, owning the potentials to accomplish low-drift and long-life memory programming, the nano-composite Sb–SiO2 PCMs hold great promise to be employed for working memory and neuromorphic computing applications.